The present invention relates to an outer sole for an athletic shoe of the type having cleats with exchangeable gripping elements that are screwed onto sole-mounted threaded studs.
An athletic shoe having a sole of this kind is described in U.S. Pat. No. 2,302,471, where a kind of flat headed screw is inserted through the shoe sole from the inside, and a washer and locking disk are secured by a nut onto the exteriorly projecting threaded shaft. Moreover, a cone-shaped gripping element, having teeth at its base, is screwed onto the projecting threaded shaft. The teeth at the base of the gripping element form a locking engagement, when screwed onto the shoe sole, with the grip members punched out from the washer. To ensure locking action, the washer has exteriorly toothed ring elements that cut into the shoe sole. A threaded sleeve is molded into the bore of the cap, which consists of deformable material, like rubber, to ensure firm anchoring thereof.
However, this known construction has several disadvantages. Firstly, the continuous flat headed screw causes considerable weakening of the sole, which may tear at the bore edges when frequently deformed. A similar effect is caused by the sharp toothed ring elements cutting into the sole. Another drawback of the known arrangement is the necessity of the special threaded sleeve in the cap.
A similar arrangement of gripping elements is disclosed in U.S. Pat. No. 3,054,197, as can be seen from the drawings of this patent.
German O. S. No. 2,542,116 shows a grip element in the form of a conventional screw-in cleat, which additionally can be screwed onto a shallow threaded study by way of an interior thread. This threaded stud has cylindrical shape. As the gripping elements, however, advantageously should be cone shaped, this creates a thin area in the vicinity of the threaded stud in the cleat wall, which may result in breakage of the cleat due to cold weather and correspondingly stiff material.
It is the objective of the present invention to provide an outer sole for an athletic shoe having cleats with exchangeable gripping elements of the foregoing kind that are designed for easy and cost-effective manufacture, yet a premature tearing, breaking, or breaking away of the sole is prevented, while at the same time, the caps can be removed from the studs without damaging or destroying them.
Furthermore, a cone shaped stud and snap-on cap are described in German Patent GM No. 1,888,123. However, the stud and cap are nailed on, and a screw-lock engagement is not featured.
This objective is achieved by employing the special features of the invention wherein a cone shaped threaded stud projects from a ground contacting surface of the sole and a hollow, tapered screw-on cap is threadingly engageable thereon with the broad base of the cap facing the sole, wherein the threading of the stud and the cap extends for less than a full turn and wherein the cap is provided with locking elements that interact with locking elements of the sole, said locking elements forming a ratchet-like locking assembly and having run-on surfaces that are less inclined relative to a plane of a bottom surface of the sole than inclined locking surfaces of the locking elements.
The present invention provides large area contact between the threaded stud and the cap, whereby the use of special threaded sleeves is not necessary. The partial screw threads permit a quick fastening and removal with low rotational effort of the cap, and the special inclined configuration of the teeth permits a soft screwing on, while the screwing off action necessitates high rotational moment, without, however, causing any marring or damage of the locking elements. When the threaded studs are molded to the sole, only the caps, without additional components, are to be screwed on.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.